Social proof is a form of persuasion based on comparison and conformity. People compare their behavior and actions to what others are doing and will change to conform to do what their peers do.
A good example of social proof is from laugh tracks on television shows. Fullery & Skeffington (1974) found that adding group laughter sounds to material increased how humorous the participants perceived that material, regardless of whether the content itself was funny or not. By adding a laugh track to a scene on television, the perceived laughter of others serves as the trigger and persuades the viewer to also find the scene funny.
A Form of Peripheral Persuasion
When a group of people are collectively engaging in a behavior—like waiting in a long line at a donut shop—this can trigger an individual to change their own behavior to match the others—like joining everyone else in line even if they had other things they wanted to do.
Why does this work? Peripheral persuasion taps into the reflexive thought, “Everyone else is doing it; they must be on to something, so I better do the same.”
Such reactions are similar to fixed action patterns—sequences of behaviors that occur exactly the same way every time an individual is triggered. For instance, when a baby cries, a mother is triggered and reflexively soothes the baby until the baby stops crying. If someone points up at the sky, the person next to them reflexively looks up to see what is there.
When we encounter circumstances that trigger these auto-pilot reactions, such situations can be persuasive in changing our thoughts and behaviors. For example, when a product is advertised with cute animals, the ad can reflexively provoke a feeling of joy that is not directly relevant to the product but still persuades the individual to buy it.
On the one hand, responding to these triggers with mindless actions can be an effective shortcut to make decisions quickly, especially considering the overwhelming amount of information that we are faced with every day. But, on the other hand, this path leaves individuals susceptible to psychological manipulation, persuading them to commit actions they could later regret (Levine, 2019).
Dimensions of Social Proof
Contrary to social proof and its emphasis on conforming to others, the peripheral persuasion tactic of commitment and consistency emphasizes conforming to the self and one’s own past decisions. When we are faced with a decision that is similar to a choice we have already made in the past, this situation triggers a desire to be perceived as consistent and persuades us to commit to behaving the same way again.
But, what makes someone more vulnerable to social proof persuasion or to commitment/consistency persuasion? One possible explanation is cultural context. Some cultures are more individualistic—focused on serving needs of self before others and self-oriented—whereas others are more collectivistic—focused on serving needs of others before self and group-oriented (Triandis, 1988). So, you might expect that for a collectivistic culture, social proof and conforming to the group may be more persuasive than a commitment/consistency tactic.
To test whether this hypothesis was correct, Cialdini et al. (1999) conducted a study with students from a predominantly individualistic culture (the United States) and from a predominantly collectivistic culture (Poland). The experimenters wanted to know how likely the students were to complete an unpaid survey, and they primed half the students to take into account how compliant their peers were and the other half to take into how account how compliant the students themselves had previously been. Knowing how compliant their peers were was more influential for the Polish students, whereas knowing how compliant they would be to previous decisions was relatively more persuasive for the American students.
Not Simply Cultural
When the researchers further analyzed the data based on how individualistic or collectivistic each student was, regardless of their nationality, this personalized orientation predicted whether social proof or consistency/compliance was more persuasive. So, while culture is influential variable, someone’s own personal orientation to individualistic or collectivistic behavior is also important in whether they are persuaded by social proof or commitment/consistency.